How can I solve the error in Buildphares Xcode in Flutter?

Question

I'm trying to implement my home widget in flutter with this plugin:

home_widget

As it is written in the iOS Added Guide in my XCode app this Build Phases:

generatedPath="$SRCROOT/Flutter/Generated.xcconfig"
versionNumber=$(grep FLUTTER_BUILD_NAME $generatedPath | cut -d '=' -f2)
buildNumber=$(grep FLUTTER_BUILD_NUMBER $generatedPath | cut -d '=' -f2)
/usr/libexec/PlistBuddy -c "Set :CFBundleVersion $buildNumber" "$SRCROOT/WidgetHome/Info.plist"
/usr/libexec/PlistBuddy -c "Set :CFBundleShortVersionString $versionNumber" "$SRCROOT/WidgetHome/Info.plist"

But when I run it, it comes out:

   Set: Entry, ":CFBundleVersion", Does Not Exist
    Set: Entry, ":CFBundleShortVersionString", Does Not Exist
    Command PhaseScriptExecution failed with a nonzero exit code